IdentityHashMap get() Method in Java

Last Updated : 23 Jul, 2018

The java.util.IdentityHashMap.get() method of IdentityHashMap class is used to retrieve or fetch the value mapped by a particular key mentioned in the parameter. It returns NULL when the map contains no such mapping for the key. Syntax:

IdentityHashMap.get(Object key_element)

Parameter: The method takes one parameter key_element of object type and refers to the key whose associated value is supposed to be fetched. Return Value: The method returns the value associated with the key_element in the parameter. Below programs illustrates the working of java.util.IdentityHashMap.get() method: Program 1:

Java

// Java code to illustrate the get() method
import java.util.*;

public class Identity_Hash_Map_Demo {
    public static void main(String[] args)
    {

        // Creating an empty IdentityHashMap
        Map<Integer, String> identity_hash = 
              new IdentityHashMap<Integer, String>();

        // Mapping string values to int keys
        identity_hash.put(10, "Geeks");
        identity_hash.put(15, "4");
        identity_hash.put(20, "Geeks");
        identity_hash.put(25, "Welcomes");
        identity_hash.put(30, "You");

        // Displaying the IdentityHashMap
        System.out.println("Initial Mappings are: " + 
                                       identity_hash);

        // Getting the value of 25
        System.out.println("The Value is: " + 
                                identity_hash.get(25));

        // Getting the value of 10
        System.out.println("The Value is: " + 
                                identity_hash.get(10));
    }
}

Output:

Initial Mappings are: {10=Geeks, 30=You, 20=Geeks, 25=Welcomes, 15=4}
The Value is: Welcomes
The Value is: Geeks

Program 2:

Java

// Java code to illustrate the get() method
import java.util.*;

public class Identity_Hash_Map_Demo {
    public static void main(String[] args)
    {

        // Creating an empty IdentityHashMap
        Map<String, Integer> identity_hash = 
               new IdentityHashMap<String, Integer>();

        // Mapping int values to string keys
        identity_hash.put("Geeks", 10);
        identity_hash.put("4", 15);
        identity_hash.put("Geeks", 20);
        identity_hash.put("Welcomes", 25);
        identity_hash.put("You", 30);

        // Displaying the IdentityHashMap
        System.out.println("Initial Mappings are: " + 
                                       identity_hash);

        // Getting the value of "Geeks"
        System.out.println("The Value is: " + 
                          identity_hash.get("Geeks"));

        // Getting the value of "You"
        System.out.println("The Value is: " + 
                            identity_hash.get("You"));
    }
}

Output:

Initial Mappings are: {Geeks=20, Welcomes=25, You=30, 4=15}
The Value is: 20
The Value is: 30

Note: The same operation can be performed with any type of Mappings with variation and combination of different data types.

IdentityHashMap hashCode() Method in Java

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